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 * Copyright (c) 2016, 2021, Oracle and/or its affiliates.
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 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
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 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided
 * with the distribution.
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 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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package com.oracle.truffle.llvm.runtime.nodes.intrinsics.llvm.va;

import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.ImportStatic;
import com.oracle.truffle.api.dsl.NodeChild;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.library.CachedLibrary;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMExpressionNode;
import com.oracle.truffle.llvm.runtime.nodes.func.LLVMCallNode;
import com.oracle.truffle.llvm.runtime.nodes.intrinsics.llvm.va.LLVMVaListStorage.VAListPointerWrapperFactoryDelegate;
import com.oracle.truffle.llvm.runtime.pointer.LLVMPointer;

/**
 * The node handling the <code>va_start</code> instruction. It basically just delegates to
 * {@link LLVMVaListLibrary}.
 */
@NodeChild
@ImportStatic(LLVMVaListStorage.class)
public abstract class LLVMVAStart extends LLVMExpressionNode {

    private final int numberOfExplicitArguments;

    public LLVMVAStart(int numberOfExplicitArguments) {
        this.numberOfExplicitArguments = numberOfExplicitArguments;
    }

    static Object[] getArgumentsArray(VirtualFrame frame) {
        Object[] arguments = frame.getArguments();
        Object[] newArguments = new Object[arguments.length - LLVMCallNode.USER_ARGUMENT_OFFSET];
        System.arraycopy(arguments, LLVMCallNode.USER_ARGUMENT_OFFSET, newArguments, 0, newArguments.length);

        return newArguments;
    }

    @Specialization
    protected Object vaStart(VirtualFrame frame, LLVMPointer targetAddress,
                    @Cached VAListPointerWrapperFactoryDelegate wrapperFactory,
                    @CachedLibrary(limit = "3") LLVMVaListLibrary vaListLibrary) {
        Object vaList = wrapperFactory.execute(targetAddress);
        vaListLibrary.initialize(vaList, getArgumentsArray(frame), numberOfExplicitArguments, frame);
        return null;
    }
}
